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/*
* Copyright (c) 2011-2015 Richard Braun.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Upstream site with license notes :
* http://git.sceen.net/rbraun/librbraun.git/
*/
#ifndef CPU_H
#define CPU_H
#include <sched.h>
#include "macros.h"
/*
* Maximum number of supported processors.
*/
#define NR_CPUS CONFIG_NR_CPUS
/*
* Filter invalid values.
*
* The maximum number of processors must be a power-of-two in order to avoid
* divisions.
*/
#if (NR_CPUS < 1) || !ISP2(NR_CPUS)
#error "invalid number of configured processors"
#endif
/*
* L1 cache line shift and size.
*/
#define CPU_L1_SHIFT CONFIG_CPU_L1_SHIFT
#define CPU_L1_SIZE (1 << CPU_L1_SHIFT)
/*
* Return the ID of the currently running CPU.
*
* This implementation uses a glibc-specific function that relies on a
* Linux-specific system call to obtain the CPU ID. If this function fails
* (e.g. when run in valgrind), 0 is returned.
*
* The returned CPU ID cannot be greater than the maximum number of supported
* processors.
*/
static inline int
cpu_id(void)
{
#if NR_CPUS == 1
return 0;
#else
int id;
id = sched_getcpu();
if (id == -1) {
return 0;
} else if (id >= NR_CPUS) {
id &= (NR_CPUS - 1);
}
return id;
#endif
}
#endif /* CPU_H */
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